Fabrizio Tamburini, the Italian researcher who has discovered an innovative way to multiply the transmission of electromagnetic signals by exploiting the vorticity of photons, has received last Saturday the "San Valentino prize" at Palazzo Gazzolli in Terni, Italy.

The annual prize was founded in 1969 by Agostino Pensa and is meant to recognize the professional devotion of scientist and artists to their work. In the past years the prize has gone, among others, to several distinguished physicists: Ugo Amaldi, Carlo Rubbia, Emilio Segre', Tullio Regge.

Tamburini (left in the above picture at the prize giving in Terni), who until a few years ago was a practically unknown researcher with no permanent position and allegedly scarce prospects of a career in academia, is the mastermind of a groundbreaking discovery which is going to revolutionize the world of electromagnetic transmissions. He is a striking example of how Italy is incapable of recognizing the talent of its scientists. Now he does not need the support of Academia any longer: he is receiving offers from the major companies in the world, eager to exploit his patented techniques. Below is a token of appreciation he recently received from one of those companies -a Ferrari. Tamburini is an avid pilot and he often regrets having chosen physics rather than professional driving competitions as a career - but we are all happy that he ended up as a scientist!

Along with his collaborators, Tamburini has recently produced experimental evidence that radio techniques can be used for
synthesizing and analyzing non-integer electromagnetic (EM) orbital
angular momentum (OAM) of radiation. The technique used
amounts to sample, in space and time, the EM field vectors and digitally
processing the data to calculate the vortex structure, the spatial
phase distribution, and the OAM spectrum of the radiation. The
experimental verification that OAM-carrying beams can be readily
generated and exploited by using radio techniques paves the way to an
entirely new paradigm of radar and radio communication protocols.

Comments

So I just found [1] and if I understood it correctly, OAM is an additional modulation method which can be applied additionally to existing modulations like AM, FM and PM? Adding another dof which is intrinsic to it's frequency that means? Now that's really novel.
Do you know if OAM can only applied to entangled photon-pairs? That's something I didn't quite understood yet (and also has implications on the feasibility in real-life applications outside a lab).
Also, how many wavelengths does it take to pack in a single bit of information?

I've got to disagree with Tommaso on this one. This sounds over hyped: "... is the mastermind of a groundbreaking discovery which is going to revolutionize the world of electromagnetic transmissions..."

Now, trying to think this out myself. I think it comes down to: Are we missing any free modes in electromagnetism when we use horizontal and vertically polarized modes as our basis?

Tommaso, what do you think? Are we neglecting some free modes when we do this?

Orbital angular momentum (OAM) modes can be decomposed into spatial distributions of the polarization freedoms. So this is nothing more than MIMO, and it is being severely misrepresented as a "groundbreaking discovery" allowing potentially infinite channels because there are infinite OAM modes.

I have yet to read this paper, but from the abstract it sounds for reasons similar to what I gave above, that the radio channel claims by Fabrizio Tamburini would lead to a violation of the second law of thermodynamics.http://vixra.org/abs/1209.0107

In short, there is a lot of reason to be skeptical that these radio techniques provides anything beyond techiques already in use for radio communications today. It does not appear far field radio communications will be able to benefit from this. It is science after all, so let's go test the idea. But extraordinary claims require extraordinary proof.

Lagrangians, the tests have already taken place. I think you need to read the literature and thengive a look at the demonstrations. Unfortunately I have no links in English handy... I willlook for some information

Tommaso,
I agree with the skeptics here. It's one thing to use OAM modes with some wave guide or laser beam, but it is still fundamentally using spatial distribution to encode the extra information. This is not an extra degree of internal freedom. That is why this cannot be used in far field radio transmissions.

I think Lagrangians's question helps point this out, but you avoided answering. I'll reword it here slightly:
If we use right and left circular polarization, overall phase, and momentum as our basis for free electromagnetic radiation, are you actually claiming we are missing some modes ... that there are extra degrees of freedom we can't build from this?

Tommaso, I'm curious to here your answer.
Hopefully pondering on that will help you understand why Fabrizio's claims are likely wrong. This is nothing more than MIMO.

I've never seen someone point out and discuss the nationality of researchers as much as Tommaso does.
If some guy in Russia was making these grandious claims about radio waves, do you think Tommaso would still buy it despite all the skeptics? No, I honestly don't.

Everyone has their biases, but I wish Tommaso would be more aware of his.
There is nothing quantum going on here. It is classical radio emmisions. This is just MIMO, pure and simple.

it's funny, but you couldn't be farther from the truth. I am an internationalist :)While Tamburini is indeed a friend of mine, I am the last one in a long row ofenthusiasts for his work. And the fact that he is being pampered by big companiesshould tell you that this is not a theoretical development with no applications butsomething that will soon be used in the telecommunications industry.

About Rossi: I hope he changes nationality. If you read between the lines of mypost on his E-CAT and the comments thread you can easily make up your mind aboutwhat I think of his device (it's a scam).

And the fact that he is being pampered by big companies should tell you that this is not a theoretical development with no applications but something that will soon be used in the telecommunications industry.

This is not a very convincing argument to counter the issues people have brought up. I can see what the skeptics are saying, but I don't really understand what your stance is here.

Do you at least agree with Steve that these radio transmissions are in the classical realm of Maxwell's equations?

And John's question regarding the fundamental degrees of freedom here is also relevant. I too am curious about your answer to that.

Tamburini thinks that the bandwidth available to mobile phones and laptop computers could be increased by a factor of nine almost immediately, and at relatively little extra cost, by carefully positioning four antennas inside the devices. He estimates that this technology could enter the market within the next two to five years. Technological improvements could make even more bandwith available.

Taco Visser, an electrical engineer at Delft University of Technology in the Netherlands, thinks that twisted radio beams would "certainly increase capacity" in telecommunication channels. But he cautions that atmospheric turbulence, which causes fluctuations in the amplitude and phase of a signal, would probably limit the extent to which beams could be twisted and therefore restrict the number of available channels. He also says it is not clear how portable devices such as mobile phones could emit such twisted beams, because each channel would require its own spiral reflector.

This is indeed a great technical acchievement, and I was fortune enough to see a demonstration of the technique some time ago, using two channels with the oldschool parabola antenna which could be tuned between the fundamental mode and the OAM mode. Very impressive.
I also saw that some electrical engineers couldnt believe that a physicist can revolutionize their field. Several of those engineers wrote critical comments, but it turned out they usually lack of fundamental understandings of Maxwell equations. :)

1. Every EM field from any arbitrary radio or TV antenna, laser, light bulb, star or whatever object that emits radiowaves, lightwaves etc carry angular momentum density. Precisely as they all carry energy and linear momentum density (also known as Poynting vector). This follows directly from Maxwell's equations.

2. Wave polarisation (left-hand/right-hand, or horizontal/vertical) is the spin part of the electromagnetic angular momentum. It is therefore called SAM (spin angular momentum) and is entirely different from the OAM which is the orbital part of the angular momentum. It is precisely as with the motion of the earth. It spins on its own axis at a rate of approximately 1 rev per 24 h. This is the earhts SAM. It also orbits around the suna ta a rate of about 1 rev per 365 days. This is the earth's OAM. The SAM (24 h) and the OAM (365 days) have nothing to do with each other. The same is true for photons/electromagnetic fields.

3. MIMO is based on the use of multiple antennas. It is *necessary* for MIMO to be able to increase the spectral capacity to use multiple antennas at both the transmitting and receiving end. OAM can increase the spectral capacity using only a single antenna at the transmitting and receiving ends. The fact that it is *possible* or *sufficient* to use multiple antennas to generate and detect OAM (at least approximately) does not mean that it is *necessary*.

Transferring information wirelessy with electromagnetic (EM) fields amounts to encoding information
onto physical observables carried by these fields, radiating them into the surrounding space, and
detecting them remotely by an appropriate sensor connected to an information-decoding receiver. Each
observable is second order in the fields and fulfills a conservation law. Of all available observables,
only the linear momentum is fully exploited in present-day radio. A fundamental physical limitation of
this observable, which represents the translational degrees of freedom of the fields and of the charges
(typically an oscillating electric current along a linear antenna), is that it is single-mode. This means that
a linear-momentum radio communication link comprising one transmitting and one receiving antenna,
known as a single-input-single-output (SISO) link, can provide only one transmission channel per
frequency (and polarization). In contrast, angular momentum, which represents the rotational degrees
of freedom, is multi-mode, allowing an angular-momentum SISO link to accommodate an arbitrary
number of independent transmission channels on one and the same frequency (and polarization).